﻿#region Header

// <file>
//     <copyright see="prj:///doc/copyright.txt"/>
//     <license see="prj:///doc/license.txt"/>
//     <owner name="Mike Krüger" email="mike@icsharpcode.net"/>
//     <version>$Revision: 3050 $</version>
// </file>

#endregion Header

namespace ICSharpCode.TextEditor
{
    using System;
    using System.Drawing;
    using System.IO;
    using System.Reflection;
    using System.Windows.Forms;

    using ICSharpCode.TextEditor.Document;

    /// <summary>
    /// This class views the line numbers and folding markers.
    /// </summary>
    public class GutterMargin : AbstractMargin, IDisposable
    {
        #region Fields

        public static Cursor RightLeftCursor;

        StringFormat numberStringFormat = (StringFormat)StringFormat.GenericTypographic.Clone();

        #endregion Fields

        #region Constructors

        static GutterMargin()
        {
            Stream cursorStream = Assembly.GetCallingAssembly().GetManifestResourceStream("ICSharpCode.TextEditor.Resources.RightArrow.cur");
            if (cursorStream == null) throw new Exception("could not find cursor resource");
            RightLeftCursor = new Cursor(cursorStream);
            cursorStream.Close();
        }

        public GutterMargin(TextArea textArea)
            : base(textArea)
        {
            numberStringFormat.LineAlignment = StringAlignment.Far;
            numberStringFormat.FormatFlags   = StringFormatFlags.MeasureTrailingSpaces | StringFormatFlags.FitBlackBox |
                StringFormatFlags.NoWrap | StringFormatFlags.NoClip;
        }

        #endregion Constructors

        #region Properties

        public override Cursor Cursor
        {
            get {
                return RightLeftCursor;
            }
        }

        public override bool IsVisible
        {
            get {
                return textArea.TextEditorProperties.ShowLineNumbers;
            }
        }

        public override Size Size
        {
            get {
                return new Size((int)(textArea.TextView.WideSpaceWidth
                                      * Math.Max(3, (int)Math.Log10(textArea.Document.TotalNumberOfLines) + 1)),
                                -1);
            }
        }

        #endregion Properties

        #region Methods

        public void Dispose()
        {
            numberStringFormat.Dispose();
        }

        public override void HandleMouseDown(Point mousepos, MouseButtons mouseButtons)
        {
            TextLocation selectionStartPos;

            textArea.SelectionManager.selectFrom.where = WhereFrom.Gutter;
            int realline = textArea.TextView.GetLogicalLine(mousepos.Y);
            if (realline >= 0 && realline < textArea.Document.TotalNumberOfLines) {
                // shift-select
                if((Control.ModifierKeys & Keys.Shift) != 0) {
                    if(!textArea.SelectionManager.HasSomethingSelected && realline != textArea.Caret.Position.Y) {
                        if (realline >= textArea.Caret.Position.Y)
                        { // at or below starting selection, place the cursor on the next line
                            // nothing is selected so make a new selection from cursor
                            selectionStartPos = textArea.Caret.Position;
                            // whole line selection - start of line to start of next line
                            if (realline < textArea.Document.TotalNumberOfLines - 1)
                            {
                                textArea.SelectionManager.SetSelection(new DefaultSelection(textArea.Document, selectionStartPos, new TextLocation(0, realline + 1)));
                                textArea.Caret.Position = new TextLocation(0, realline + 1);
                            }
                            else
                            {
                                textArea.SelectionManager.SetSelection(new DefaultSelection(textArea.Document, selectionStartPos, new TextLocation(textArea.Document.GetLineSegment(realline).Length + 1, realline)));
                                textArea.Caret.Position = new TextLocation(textArea.Document.GetLineSegment(realline).Length + 1, realline);
                            }
                        }
                        else
                        { // prior lines to starting selection, place the cursor on the same line as the new selection
                            // nothing is selected so make a new selection from cursor
                            selectionStartPos = textArea.Caret.Position;
                            // whole line selection - start of line to start of next line
                            textArea.SelectionManager.SetSelection(new DefaultSelection(textArea.Document, selectionStartPos, new TextLocation(selectionStartPos.X, selectionStartPos.Y)));
                            textArea.SelectionManager.ExtendSelection(new TextLocation(selectionStartPos.X, selectionStartPos.Y), new TextLocation(0, realline));
                            textArea.Caret.Position = new TextLocation(0, realline);
                        }
                    }
                    else
                    {
                        // let MouseMove handle a shift-click in a gutter
                        MouseEventArgs e = new MouseEventArgs(mouseButtons, 1, mousepos.X, mousepos.Y, 0);
                        textArea.RaiseMouseMove(e);
                    }
                } else { // this is a new selection with no shift-key
                    // sync the textareamousehandler mouse location
                    // (fixes problem with clicking out into a menu then back to the gutter whilst
                    // there is a selection)
                    textArea.mousepos = mousepos;

                    selectionStartPos = new TextLocation(0, realline);
                    textArea.SelectionManager.ClearSelection();
                    // whole line selection - start of line to start of next line
                    if (realline < textArea.Document.TotalNumberOfLines - 1)
                    {
                        textArea.SelectionManager.SetSelection(new DefaultSelection(textArea.Document, selectionStartPos, new TextLocation(selectionStartPos.X, selectionStartPos.Y + 1)));
                        textArea.Caret.Position = new TextLocation(selectionStartPos.X, selectionStartPos.Y + 1);
                    }
                    else
                    {
                        textArea.SelectionManager.SetSelection(new DefaultSelection(textArea.Document, new TextLocation(0, realline), new TextLocation(textArea.Document.GetLineSegment(realline).Length + 1, selectionStartPos.Y)));
                        textArea.Caret.Position = new TextLocation(textArea.Document.GetLineSegment(realline).Length + 1, selectionStartPos.Y);
                    }
                }
            }
        }

        public override void Paint(Graphics g, Rectangle rect)
        {
            if (rect.Width <= 0 || rect.Height <= 0) {
                return;
            }
            HighlightColor lineNumberPainterColor = textArea.Document.HighlightingStrategy.GetColorFor("LineNumbers");
            int fontHeight = textArea.TextView.FontHeight;
            Brush fillBrush = textArea.Enabled ? BrushRegistry.GetBrush(lineNumberPainterColor.BackgroundColor) : SystemBrushes.InactiveBorder;
            Brush drawBrush = BrushRegistry.GetBrush(lineNumberPainterColor.Color);
            for (int y = 0; y < (DrawingPosition.Height + textArea.TextView.VisibleLineDrawingRemainder) / fontHeight + 1; ++y) {
                int ypos = drawingPosition.Y + fontHeight * y  - textArea.TextView.VisibleLineDrawingRemainder;
                Rectangle backgroundRectangle = new Rectangle(drawingPosition.X, ypos, drawingPosition.Width, fontHeight);
                if (rect.IntersectsWith(backgroundRectangle)) {
                    g.FillRectangle(fillBrush, backgroundRectangle);
                    int curLine = textArea.Document.GetFirstLogicalLine(textArea.Document.GetVisibleLine(textArea.TextView.FirstVisibleLine) + y);

                    if (curLine < textArea.Document.TotalNumberOfLines) {
                        g.DrawString((curLine + 1).ToString(),
                                     lineNumberPainterColor.GetFont(TextEditorProperties.FontContainer),
                                     drawBrush,
                                     backgroundRectangle,
                                     numberStringFormat);
                    }
                }
            }
        }

        #endregion Methods
    }
}